This invention relates to the production of hydro-electric energy from a fall of water through a penstock.
The present day hydro-electric system is based on water flowing into a penstock and thence by gravity flow through a scroll case. The flowing water is guided by suitable conduit means so as effectively to be a solid column of water flowing and the swirl of the water in the scroll case is directed into and drives a turbine wheel. The water passes through the wheel into a draft tube and onto the tail race. Normally, the turbine wheel and generator are situated at the lowest practical point on a gravity fall of water. Manufacturers and hydroelectric companies state that modern turbine wheels have an efficiency rating of up to 97%.
One aspect of the invention resides in a newly designed penstock, where instead of having the water as is presently done flow as a solid column through a pipe, it flows as an annular column. Another aspect resides in a re-design of the turbine wheel so as to be driven by the annular column of flowing water.
Another aspect of the invention resides in designing the system so there is laminar flow of the water.
Another principal aspect of the present invention is based on the principle of siphonage which means that the gravity rate of flow is uniform throughout the flow. In other words, the water no longer flows into a penstock as is the case with known devices but instead is drawn thereinto, the entire column acting as a siphon.
Applicant's type of penstock reduces or eliminates vortex action normally present in existing designs and the subsequent turbulent flow encountered also in the flow entrances of standard penstocks.
As will be seen hereinafter, the turbine design eliminates the use of a scroll case and a design where the leverage factor is increased substantially over a standard turbine wheel.
Another aspect of the present invention is the use of multiple turbine wheels in a confined gravity fall of water and such fall of water flowing by way of siphon action. In a low head installation, one or more turbine wheels may be mounted on a common shaft and in high head situations, a staggered arrangement is provided with multiple turbines spaced apart in the direction of flow and offset from one another so as to be located on different vertical axes.